Stable Fiber Laminate, and Method and Device for the Production Thereof

ABSTRACT

The invention relates to a fiber laminate comprising two supporting fleeces and an absorptive fiber material which is disposed between the two supporting fleeces and is strengthened by means of a hydroentanglement process. Also disclosed are a method and a device for producing such a fiber laminate. The inventive fiber laminate is provided with sufficient stability against delamination and great absorptive capacity. Zones with absorptive fiber material and zones in which the two supporting fleeces are in direct contact with each other are provided between the two supporting fleeces across the area of the fiber laminate such that zones are created in which the two supporting fleeces forming the outer layers are directly connected to each other

The invention relates to a fiber laminate which comprises two carrierwebs and absorptive fiber material inserted between the two carrier websand is bonded by hydroentanglement. The invention further relates to amethod and an apparatus for producing such a fiber laminate.

From EP 1 250 482 a method is known for the production of a compositenonwoven consisting of at least one carrier web, for example a spunbondweb, and one layer of wood pulp deposited on such a carrier web forproducing a hygiene product, wherein the spunbond web is consolidated indry condition for preliminary bonding prior to coating with thesuper-absorbent material, the wood pulp layer is then added and bothtogether are bonded by means of hydroentanglement and then are dried.

Furthermore EP 1 524 350 describes a fiber laminate, in particular anabsorbent cleaning cloth, consisting of at least one pre-consolidatedspunbond web made of filaments and at least one fiber layer made ofhydrophilic fibers, wherein the fiber laminate is hydrodynamicallyconsolidated and wherein embossed deformations are incorporated into thesurface of the hydrodynamically consolidated fiber laminate. Whenproducing such wiping and cleaning cloths, the two outer layersconsisting of pre-consolidated spunbond webs and the inner layerconsisting of air-laid pulp are bonded with each other byhydroentanglement.

Such products offer satisfactory properties with respect to costs andstrength values, but in practical use their insufficient thickness andabsorptive capacity are criticized. In addition, the delaminationstrength of the individual layers produced by the water jet treatment isnot sufficient so that, especially in moist condition, the layers easilyseparate again. This disadvantage is partially remedied in theabove-mentioned EP 1 524 350 by preliminary embossing of the web layersused or by subsequent embossing of the bonded end product.

It is the task of the present invention to describe a fiber laminatetogether with method and apparatus for producing the same which offerssufficient delamination stability and high absorptive capacity.

This task is solved by a fiber laminate in conformity with patent claim1 and a corresponding method and a corresponding apparatus for producingsuch a fiber laminate.

The fiber laminate according to the invention comprises two carrier websand absorptive fiber material inserted between these two carrier websand is bonded by hydroentanglement. When looking at the surface area ofthis fiber laminate, there are sections with absorptive fiber materialbetween the two carrier webs and sections where the two carrier websdirectly touch each other.

In this way, sections are created where the two carrier webs forming theoutside layers are directly connected with each other. This distinctlyincreases the delamination stability. This was demonstrated by trials inwhich the forces required for delamination were measured in dry andmoist condition of the fiber laminate. The stability in moist conditionof a fiber laminate according to the invention is very stronglyincreased compared to conventional fiber laminates. The absorptive fibermaterial is contained in individually separated square sections betweenthe two carrier webs. The overall impression of the fiber laminate isthat of a knobbed nonwoven with embeddings similar to a quilt.

In the process for production of such a fiber laminate absorptive fibermaterial is placed between two carrier webs. The three layers, namelythe two carrier webs with the absorptive fiber material placed inbetween, are consolidated by means of hydroentanglement using astructuring perforated template with the openings in the template beingof just such a size that the absorptive fiber material between the twocarrier webs is washed away from the sides of the webs of the templatetoward the openings of the template by the water jet treatment. For thispurpose, a corresponding device for production of the fiber laminate isprovided with a structuring perforated template having openings with adiameter between 0.5 and 20 mm. Contrary to the known openings in amicroporous shell, these openings are distinctly bigger because they arenot designed for draining any liquid but for taking up the fibers of theabsorptive fiber material between the two carrier webs which are washedaway from the webs of the template. The width of the webs is preferablyselected within a range from 1 to 5 mm.

The carrier webs either consist of spunbond webs or layers made ofstaple fibers which are preferably pre-bonded in dry condition, forexample by calendering.

The absorptive fiber material favorably consists of a pulp layer, suchas tissue, or a super-absorbent layer.

The areal weight of the carrier webs usually ranges from 3 to 18 g/cm2and in particular from 6 to 10 g/cm2. The average areal weight of theabsorptive fiber material preferably lies between 8 and 100 g/cm2 and inparticular between 20 and 50 g/cm2.

The areas of absorptive material are preferably distributed over thesurface of the fiber laminate in such a way that they provide the fiberlaminate with a knobbed structure. It is also conceivable to use suchstructures of an arbitrary geometry in order to provide the fiberlaminate with an attractive optical design as, for example, in the shapeof a flower pattern formed by several structures.

The structuring template is favorably designed as drum shell or endlessshell.

The invention will be exemplified below by reference to the drawing.

In a lateral cross-section through a fiber laminate above a section of adrum shell, water jets 10 meet the fiber laminate, which consists firstof a carrier web 1 made of spunbond web at the top, absorptive fibermaterial 2 underneath and a second carrier web 3 also made of spunbondweb at the bottom. In an area 12 seen over the surface of the fiberlaminate, absorptive fiber material 2 is included between the topcarrier web 1 and the bottom carrier web 3. In an area 13 top carrierweb 1 and bottom carrier web 3 are in direct contact with each other.This structure is explained by the water jets 10 impinging from the topwashing away the absorptive fiber material 2 from a web 7 of thetemplate 4 toward the side in the direction of the openings 6 of thetemplate 4. The impact of the water jets 10 thus literally forces theabsorptive fiber material 2 away from the web 7 in the direction of theopenings 6. Located underneath the structuring template 4 is asupporting wire mesh 5 with a supporting drum shell 11 underneath. Thesupporting wire mesh 5 can be generally designed as a porous boyd oralso as a microporous shell. Shown beside the openings 6 of the template4 is a distinctly smaller capillary opening 8, which is used for removalof water and for this purpose has a rather small diameter in a range ofless than 0.45 mm.

REFERENCE LIST

1 first carrier web

2 absorptive fiber material

3 second carrier web

4 structuring template

5 supporting wire mesh

6 opening in the template

7 web between the openings of the template

8 capillary opening

10 water jets

11 supporting drum shell

12 area with absorptive fiber material

13 area where the two carrier webs come into direct

1. Fiber laminate which comprises two carrier webs (1, 3) and absorptivefiber material (2) inserted between the two carrier webs (1, 3) and isbonded by hydroentanglement, characterized in that, seen over thesurface of the fiber laminate, there are areas (12) with absorptivefiber material (2) between the two carrier webs (1, 3) and areas (13)where the two carrier webs (1, 3) come into direct contact.
 2. Fiberlaminate according to claim 1, characterized in that the carrier webs(1, 3) independently of each other are formed either as a layer ofspunbond web or a staple fiber layer.
 3. Fiber laminate according toclaim 1 or 2, characterized in that the absorptive fiber material (2)consists of a pulp layer or a super-absorbent layer.
 4. Fiber laminateaccording to one of the preceding claims, characterized in that thecarrier webs (1, 3) are pre-bonded in dry condition.
 5. Fiber laminateaccording to one of the preceding claims, characterized in that theareal weight of the carrier webs (1, 3) lies between 3 and 18 g/cm2, andin particular between 6 and 10 g/cm2.
 6. Fiber laminate according to oneof the preceding claims, characterized in that the average areal weightof the absorptive fiber material (2) lies between 8 and 100 g/cm2, andin particular between 20 and 50 g/cm2.
 7. Fiber laminate according toone of the preceding claims, characterized in that the areas (12) withabsorptive fiber material (2) between the two carrier webs (1, 3)provide the fiber laminate with a knobbed structure.
 8. Method forproduction of a fiber laminate comprising two carrier webs (1, 3) andabsorptive fiber material (2) inserted between the two carrier webs(1,3), wherein the fiber laminate is bonded by hydroentanglement over astructuring perforated template (4), characterized in that theabsorptive fiber material (2) is washed away from the sides of the webs(7) by the water jet treatment in the direction of the openings (6) ofthe template (4).
 9. Apparatus for production of a fiber laminatecomprising two carrier webs (1, 3) and absorptive fiber material (2)inserted between the two carrier webs (1,3), including a device bondingthe fiber material (2) by hydroentanglement, characterized in that thedevice comprises a structuring perforated template (4) with openings (6)having diameters between 0.5 and 20 mm.
 10. Apparatus according to claim9, characterized in that the perforated template (4) is designed asstructuring drum shell.
 11. Apparatus according to claim 9,characterized in that the perforated template (4) is designed asstructuring endless belt.